1. Field of the Invention
This invention relates to a fastener feeding apparatus and more particularly to an apparatus for scooping up, properly orienting, and feeding a plurality of fasteners which are stored in bulk form in a hopper.
2. Prior Art
In the case of fasteners such as screws, rivets, pins, or the like consisting of a head part and a leg part which are to be successively fed to an apparatus such as a single fastener dispensing unit from which they may be delivered one at a time to an automatic fastening tool such as an automatic screw driver, automatic riveter, automatic pin inserter tool, or the like, in the prior art, a plurality of such fasteners stored in bulk form in a hopper may be scooped up by a scooping plate pivotally moving up and down in a hopper and transferred to an obliquely supported chute rail. From the chute rail, the fasteners may be fed by gravity into a dispensing unit placed at the lower end of the chute rail. Such prior art apparatus is shown in Japanese patent publication No. 36392/79 and also in Japanese Utility Model publication No. 65185/79. However, such prior art fastener feeding apparatus has several drawbacks including the following: The fasteners being fed do not always point downward against the upper surface of the chute rail; also, their respective head parts may mutually overlap. Moreover, in the case of comparatively long fasteners, the leg part of the first fastener to be output and the leg part of a second fastener may both enter the dispensing unit simultaneously, causing a blockage of the entrance thereof and preventing any more fasteners from being dispensed. Furthermore, dust and oil may cling to the chute rail, preventing the fasteners from being properly fed. Further, when the fasteners having a short shank are fed by such an apparatus, if the adjustment to the fasteners is not made properly, the fasteners occassionally fall out. In other words, such an apparatus has a problem that it is unable to feed the fasteners securely.
In other prior art, such as is shown in Japanese patent application publication No. 2567/73, the fastener feeding apparatus is constructed in such a manner that a barrel rotatably supported on a base is provided with a scooping member therein for scooping up fasteners, said barrel and scooping member being caused to rotate by a motor. A generally horizontal conveyor rail which passes through the opening of the barrel is also provided. However, in such feeding apparatus, since the fasteners are scooped up by the rotating barrel, they are continuously being stirred up whenever the apparatus is in motion. As a result, the fasteners are easily scratched and stripped of their coatings. Moreover, as a powerful motor is required for rotating the barrel, the whole apparatus is relatively large. Furthermore, in the type of prior art described above, several of the thus scooped up fasteners may protrude upwards due to the mutual overlapping of their respective head parts and may be deposited on the chute rail in an inclined or overturned position, that is to say, in an disorderly or randomly oriented fashion. To return such randomly oriented fasteners to the hopper, there may be provided an excluding means in the form of an impeller such as is illustrated in Japanese patent publication No. 3776/69 which allows only properly oriented fasteners to pass through. By rotating the excluding impeller while the apparatus is in operation, the randomly oriented fasteners will be forced back into the hopper. However, in the process of excluding the improperly oriented fasteners, the surface of the fasteners may be scratched and the fasteners may be jammed into the space between the chute rail and the excluding impeller. Furthermore, the manufacture of such an including impeller is quite complicated.